The advent of improved photocopy equipment, mainly high-resolution color photocopy equipment, has presented a real challenge to thwart the unauthorized duplication of original documents. The quality of the reproductions is often so good that, it may be difficult to distinguish original copies from color reproductions. Many methods, products and security features have been developed to prevent the unauthorized reproduction of original valuable documents, such as currency, traveler's checks, checks, coupons, gift certificates, licenses, passports, personal identification papers, as well as packaging material for brand protection to deter illegal activities such as counterfeiting. Generally these methods, products and security features may be formed by a pattern of dots, lines, screen structures or the like. Within the background pattern, additional information can be printed that is mostly hidden by the background pattern when viewed by a casual observer. The additional information typically includes a security warning such as the word “VOID” or “COPY”. The security warning may become prominent on the copy such that even a casual observer will notice it. Thus, the original document may be easily distinguishable from its copied version by virtue of a warning such as “VOID” or “COPY” being prominently displayed on the copied version.
However, the described methods and products may be press printed documents. These documents may therefore be produced using standard press processes such as, but not limited, to offset printing (lithography), letterpress, flexographic, intaglio and gravure. The press processes may include generating film or plate, as in the case of CTP (computer to plate), at very high resolution usually at 2400 or 2540 dpi (dots per inch) to produce the pattern of dots, lines, screen structures or the likes that is required in the above described methods and products. During colorization the security feature may be assigned to one plate and/or one specific ink color, wherein the ink color may include ink of a defined PMS (Pantone Matching System) spot color or one or more of the colors in the 4-color process (Cyan, Magenta, Yellow, Black).
However, providing variable security using the above methods and processes, wherein the security features vary from document to document, each document being unique and not fixed, appears to be somewhat non-existence and cost prohibitive. It is also reportedly difficult for these technologies to be translated to lower resolution digital output devices, such as the case where the resolution of the output device maybe as low as 300 dpi (dots per inch), wherein the technologies may not remain effective against ever advancing reproduction equipment where the scanning resolution maybe as high 1200 dpi (dots per inch).
Therefore, what is needed is a document protection method and apparatus that enables a simple and expedient way to incorporate improved distortion security features, that may vary from document to document, printed on demand, printed at any resolution, printed using laser printers (including laser copier/printer) and/or ink-jet printers and/or direct image presses and/or digital presses such as but not limited to the HP Indigo, Kodak Nexpress, Versamark, Xeikon, and the Xerox IGen to prevent the unauthorized reproduction of original valuable documents through the use of photocopiers.
Moreover, what is needed are methods for producing such color original documents having such improved distortion security features calibrated, modified, transformed and/or customized for each digital output device such as laser printers and/or ink-jet printers and/or direct image presses and/or digital presses.